Process for the production of fancy



United States Patent 3,123,973 PROCESS FOR THE PRQDUCTION 0F FANCY YARNS HAVING A THREE DIMENSHONAL CURL Henri Servage, Cremieu, France, assignor to Moulinage ct Retorderie de Chavanoz, Chavanoz (Isere), France, a French body corporate No Drawing. Filed Nov. 30, 1959, Ser. No. 855,993 6 Claims. (Cl. 57157) It is known to produce high-curl yarns of the highbulk type, that is to say, yarns having a twisted threedimensional curl in alternate directions. These yarns have very high uncurling elongation. The initial process consisted in imparting a high twist to yarns consisting of continuous regenerated cellulose filaments, in treating at elevated temperature and thereafter untwisting the yarn. The yarn obtained was not stable and the effect disappeared particularly rapidly under the action of moisture.

It has been proposed to apply the same pnocess to yarns consisting of continuous cellulose acetate filaments, but the result was scarcely more favourable, especially as the eifect obtained could not be called high-bulk.

A variant has also been conceived, consisting in applying a false twist to a cellulose acetate yarn and heating the yarn at an appropriate temperature (steam treatment) while twisted.

The results obtained were scarcely more satisfactory.

The production of high-bulk yarns on an industrial scale was only developed in later years when the above treatment was applied to yarns consisting of synthetic textiles, more especiallly polyamides, which have the particular property of being able to undergo a thermal treatment producing permanent setting of the twist. This permanent setting can only be destroyed or modified by a further thermal treatment at a higher temperature.

Lengthy experiments have been made with the object of improving the twisted three-dimensional curl efiect on cellulose acetate yarns, and it has now been discovered that it is possible to obtain valuable results 'by means of an additional thermal treatment at moderate temperature applied to cellulose acetate yarns which have undergone the above-described process. This second heat treatment is preferably eifected at 75-85 C., advantageously by steaming. If the twisted cellulose acetate yarn which has been heated and untwisted is wound in such a way that it can undergo considerable shrinkage, i.e., by overfeeding, it can be steam-treated on bobbins at about 7580 C. If, on the other hand, only a small degree of shrinkage is possible on the bobbin, the thermal treatment can be applied discontinuou-sly to skeins or continuously to a yam running without appreciable tension, with any of the known devices for this purpose, for example that of addition 67,751 of the March 31, 1955 to French Patent No. 1,054,338 of the January 23, 1952, provided that the winding is effected without appreciable tension.

The invention will be more readily understood from two practical examples, but it will be obvious that these examples have no limiting character and that the invention includes any variant in the same spirit.

Example I An acetate rayon of 200 denier is twisted at 1,800 turns per metre and is steam-treated on bobbins at 95-100 C.

and thereafter untwisted, the rewinding of the untwisted yarn taking place with a shrinkage of 33%.

The packages of curled untwisted yarn are thereafter subjected to a steam treatment in an oven at C. for one hour, with preheating of the oven for half an hour. The total duration of the treatment is thus 1 hour 30 minutes. The yarn obtained has a pleasant appearance. It is not exactly a high-bulk yarn, but an interesting fancy yarn superior to the yarn obtained without the additional steam treatment.

Example 11 A cellulose acetate yarn of 200 denier, manipulated on a continuous treatment machine, with application of a false twist, undergoes a thermal treatment directly upstream of the false twist member while under tension. The process and the apparatus described in French Patent No. 1,054,338 and additions 63,983 and 66,140, notably the apparatus of French Patent No. 1,140,992 of the January 6, 1956, are employed.

A false twist of 1,850 turns per metre is applied and the false twist tubes turn at 30,000 rpm. A reduced shrinkage, e.g. up to 6% and especially from 4% to 6%, is allowed to occur during the rewinding onto the bobbins, that is to say, the rewinding speed is lower by about 20% than the speed of the supply members upstream of the heating devices. When the device according to French Patent 1,140,992 of the January 6, 1956 is employed, the heating tubes are adjusted to a temperature of :1 C.

The wound yarn is thereafter steam-treated by the usual methods, for example at 80 C. in an oven.

The products obtained are similar and constitute fancy yarns which are not true high-bulk yarns, but which have a particular appearance, which is much more distinctive than without the additional thermal treatment. However, a little of the shrinkage capacity and of the springiness is lost.

I claim:

1. A novel process for the production of fancy yarns having a cellulosic basis which comprises providing a cellulosic yarn having an original twist level; imposing a twist upon said yarn; setting the imposed twist in the yarn by heating; removing the imposed twist whereby the yarn is returned to its original twist level; winding said yarn into a package under conditions whereby the yarn is permitted to undergo considerable shrinkage; and then subjecting the yarn to a further heat treatment at a temperature of 7585 C. in the presence of steam while said yarn is substantially free from tension.

2. The process of claim 1 wherein the cellulosic yarn is a cellulose acetate yarn.

3. The process of claim 1 wherein the yarn is permit-ted to shrink by 30-35% as it is wound into a package.

4. The process of claim 1 wherein the yarn is allowed to shrink by up to 6% as it is wound into a package.

5. A novel process for the continuous production of fancy yarns having a cellulosic basis comprising providing a cellulosic yarn having an original twist level; applying a false twist to said yarn; heating the yarn while twisted to set the twist therein; removing the false twist from the yarn thereby returning the yarn to its original twist level; winding said yarn into a package under conditions whereby the yarn is permitted to undergo considerable shrinkage; and then subjecting the yarn to a Lfurther heat treatment at a temperature of 75-85 C. in the presence of steam While said yarn is substantially free from tension.

6. The process of claim 5 wherein the cellulosic yarn is a cellulose acetate yarn. 5

References Cited in the file of this patent UNITED STATES PATENTS 2,019,183 Heberlein Oct. 29, 1935 2,019,185 Kagi Oct. 29, 1935 10 2,295,593 Miles Sept. 15, 1942 2,869,318 Stucki Jan. 20, 1959 Comer et a1 Oct. 20, 1959 Breen et a1 Nov. 21, 1961 Servage Dec. 12, 1961 Heberlein Jan. 23, 1962 FOREIGN PATENTS Australia Dec. 5, 1958 Great Britain Aug. 26, 1938 Great Britain Aug. 22, 1956 Great Britain Dec. 11, 1917 Great Britain Jan. 14, 1959 France Feb. 2, 1959 

1. A NOVEL PROCESS FOR THE PRODUCTION OF FANCY YARNS HAVING A CELLULOSIC BASIS WHICH COMPRISES PROVIDING A CELLULOSIC YARN HAVING AN ORIGINAL TWIST LEVEL; IMPOSING A TWIST UPON SAID YARN; SETTING THE IMPOSED TWIST IN THE YARN BY HEATING; REMOVING THE IMPOSED TWIST WHEREBY THE YARN IS RETURNED TO ITS ORIGINAL TWIST LEVEL; WINDING SAID YARN INTO A PACKAGE UNDER CONDITIONS WHEREBY THE YARN IS PERMITTED TO UNDERGO CONSIDERABLE SHRINKAGE; AND THEN SUBJECTING THE YARN TO A FURTHER HEAT TREATMENT AT A TEMPERATURE OF 75-85*C. IN THE PRESENCE OF STEAM WHILE SAID YARN IS SUBSTANTIALLY FREE FROM TENSION. 